This invention relates to a motion picture projector for projectng a movie accompanied by a sound track. More particularly, this invention relates to an improved unitary chassis system which causes the projector to have a lower, internal operating temperature.
Many movie picture projectors have been produced which permit a movie to be shown with an audio track on the film to provide accompanying sound for the movie. In the past the particular placement of the electrical components which operate at a relatively high temperature, namely the transformer and the amplifier, was not considered to be an important criteria as far as the operating temperature of the projector was concerned. This was true primarily because of the fact that the incandescent light source is the major item which contributes to a high operating temperature for the projector. The electrical components were designed and placed within the projector cabinet at any convenient location. The disadvantage to this practice is that, although the amount of heat contributed by the electrical components is relatively small compared to the light source, they nevertheless cause a higher operating temperature of the overall projector.
In the present invention, cool air is drawn into the projector from the external environment, first across the electrical components (amplifier, transformer and motor) and thereafter across the light source and back into the environment. This design permits for the use of the largest possible temperature gradient between the electrical components and the air to more effectively cool these components. While the air is thus slightly heated before impinging the light source, the light source operates at such a high temperature level that the temperature gradient is not significantly affected. However, the cumulative effect of cooling the electrical components with the same air which is used to cool the light source is to provide a motion picture projector which operates at a temperature level considerably cooler than would have resulted without the aforementioned directed air flow.
An object of the present invention is to provide a single, unitarily casted chassis which mounts the electrical components in a path of air flow so that the overall operating temperature of the device is decreased, which thereby provides for a more economical projector requiring less servicing for components which wear out at a faster rate due to the high operating temperature.
In accordance with the present invention, a unitarily casted chassis is provided for relocating and mounting the major electrical and mechanical components of the film projector.
A pair of depending toothed flanges permit cool air from the surrounding environment to enter the projector from beneath the base. Additional air inlet slots are provided in a wall of the projector housing for cooling the transformer. The chassis also includes a plurality of fins in the path of air flow for directing heated air away from the transformer, and a plurality of slots which provide increased air flow across the amplifier components. Thereafter the air is directed across and cools the light source and from there flows out of the top of the projector.